BACKGROUND: Hyperhidrosis is a little known disorder, characterized by excessive production of sweat. Hyperhidrosis may occur under several circumstances and appears in body parts like armpits, hands, feet, and face, consequently causing problems to the patient like job limitation, social embarrassment, and psychological damage. OBJECTIVES: Using these theoretical views as a starting point, the study aimed to evaluate the prevalence of hyperhidrosis in Blumenau. METHODOLOGY: Utilizing interviews, the research was conducted with 500 subjects randomly approached, in the period ranging from August 21 to September 1st, 2006. RESULTS: 45 respondents (9%) matched the pre-requisites, being classified as hyperhidrosis patients. The age group most affected was from 18 to 30 years (11.8%). Hyperhidrosis was more frequent among men both in absolute (24 men against 21 women) and relative numbers (10.62% of men against 7.66% of women). The most prevalent characteristic was "at least one occurrence per week", in 91.11% of patients; the least prevalent occurrence was "cessation of sweat during sleep", in 37.77% of respondents. CONCLUSIONS: The data show that the prevalence of hyperhidrosis in Blumenau is higher when compared with other studies, thus indicating that it is not a rare phenomenon.